The present invention relates generally to a process for the preparation of sodium gamma-hydroxybutyrate (NaGHB) of general formula (I):

where M is as hereinafter defined, from gamma-butyrolactone (GBL) (II):

and a hydroxide source (M-OH) The present invention is also directed to an aqueous concentrate (with a pH of about 8 to about 10 and concentration greater than that of the final formulated drug product) of NaGHB drug substance (for formulation into a pharmaceutical drug product) which is produced in high yields in a continuous and/or continuous/batchwise reaction system. More generally, the present invention relates to a process for the saponification of lactones, especially three- to eight-membered ring lactones (IV):

for producing pharmaceutically acceptable salt species of general formula (I) and the even more general formula (V).
